Summary for anodized surface coloring Discussion
Coloring the anodized surface is discussed in terms of dye choice, alloy, and exposure rather than a single universal recipe. Rama Krishna Lingamaneni asks how to get different colors after anodizing aluminum, including the right dye conditions such as pH, temperature, adhesion, and how long the color will last. Ted Mooney, P.E. replies that the key missing information is what part is being made and what alloy it is made from, because different alloys accept anodizing and dye differently. He notes that the colors are completely adherent because they are absorbed into the anodized layer, but warns that some dyes are not suitable for exterior use because they fade quickly. The thread does not give specific dye bath pH or temperature values, so the practical takeaway is to match the dye and alloy to the intended service environment and durability needs.
Q. I would like to know how to get different colors after anodizing the aluminium components. I heard that the dyes are available but how best and under what conditions (like pH and temperature of dye solution) we can get strong / well adherent colors. What would be the typical duration over which the color won’t fade.
Rama Krishna Lingamaneni
Electrochemical Processing – Hyderabad, Andhra Pradesh, INDIA
2004
A. Please tell us what you’re trying to make, and what alloy you’re making it out of. All of the colors will be completely adherent because they are absorbed into the anodized layer. But some dyes are not suitable for exterior exposure because they will fade quickly, and some alloys will not accept anodizing and dye as well as others.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
2004
Q. Many thanks to Ted Mooney for the kind reply.
Most times, the alloy is 6061 T6. The purpose of coloring is to follow the color coding. May I know how to color the surface after anodizing.
Rama Krishna Lingamaneni [returning]
Electrochemical Processing of Materials – Andhra Pradesh, INDIA
2004
A. That is a good alloy for anodizing.
There is a U.S. idiom, “this is like pulling teeth”, which seems to apply here. You still haven’t forthrightly answered me with what you are trying to do, which is causing this dialog to be of limited value and to drag on slowly and painfully :-) But in concept, dyeing anodized parts is simple: Immediately after anodizing them and before sealing them you immerse them in a warm water solution into which the dye has been dissolved. The dye is soaked up into the pores of the anodizing layer, and when you subsequently seal the parts, the dye stays locked in.
You can use simple fabric dyes for low quality results, or you can use proprietary dyes which have been tweaked to work optimally on anodized parts. In this case the dye supplier will be knowledgable about anodizing, and will have had much experience in running parts through the dye, and will include in his technical data sheet the temperature, pH, and other parameters that he has found to work optimally for that one particular dye. Good luck!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
2004